Fea-bella filled two waterskins from the rivulet, and noticed the lint in the water. Then, the Ob 4 Dungeoneering check, for the PCs to successfully enter via the cleft, succeeded. The PCs saw the body that the lint had come from. I explained that the body looked as if it had fallen from the cleft more-or-less head first, and suffered a broken neck. This was how the clay pot had survived, cushioned by the body. It was mostly skeletal, years old.
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I then had one of the evil water spirits speak, but the PCs took it to be the ghost of the dead body. It urged them to drink, but they didn't want to drink corpse water, and Fea-bella emptied the waterskins she had filled. Telemere led the retort to the spirit, and offered to help them find peace. So I declared him the captain in the Trickery conflict that the spirit had initiated. The PCs' disposition was 5, vs the spirits' 10. I equipped Malicious Pranks, and scripted Feint/Attack/Attack; the players scripted Manoeuvre as their first action - and in the ensuing independent tests, I knocked off their whole disposition while losing none of my own.
I then had the talking spirit narrate something (I can't remember what it was now, but the players found it suitably confusing for a feint), while I secretly noted that the second spirit had been able to (maliciously) defile all their water. The players were uncertain what, exactly, had happened as a result of them losing the contest - but I didn't have to wait all that long before I had the chance to reveal the truth of the trick.
I described the two ways on in the antechamber, and the PCs lit two candles - one with Golin and one with Fea-bella, leaving Telemere in dim light - and chose to descend the stairs. When I described the ammoniac smell, they (correctly) inferred it was bat guano, and Golin's player, playing Golin's Explosives-wise, mooted the possibility of blowing things up. It turned out that he got his wish!
When they got to the base of the stairs, I described the statue's legs, but with only candle light they couldn't make out its upper body. Then three troll bats swooped on them. I offered to default to a drive-off conflict, but Golin wanted to capture them: he equipped his large sack to trap them in, Fea-bella equipped some fresh rations to lure them in, and Telemere equipped his spear. The PCs won this conflict handily, and so ended with a sack full of bats.
This was the fourth turn on the grind, and so the PCs became hungry and thirsty. Fea-bella and Telemere each ate a portion of fresh rations, and Golin took a sip of water. Which was defiled by the spirits, and so rather than quench his thirst it made him Sick! I thought this was hilarious, but the players didn't fully agree. It only got better when Telemere made a Survivalist test to check if all their water was spoiled, and didn't roll a single success. So he got Sick too!, from tasting some of the tainted water as part of his inspection of it. Golin ate some food to recover from his hunger. And they all emptied their waterskins.